OBJECTIVES: Ulcerative colitis (UC) is a chronic inflammatory disease of unknown etiology　that often relapses after remission. In Japan, the number of UC patients has increased recently and are expected to rise over the next decade. According to a survey conducted by the Ministry of Health, Labor and Welfare (MHLW), it was estimated to be approximately 171,000 in FY2014. The objective of this study was to estimate the annual medical cost of UC treatment in Japan.

METHODS: The annual medical cost of UC treatment (May 2014 – April 2015) was calculated using the claims database of Japan Medical Data Center Co., Ltd.. Inclusion criteria of the analyzed population were 1) UC (ICD-10 code: K51), not Crohn's disease (K50), 2) diagnosis of UC before May 2014, and 3) more than one visit between May 2014 and April 2015. Hospitalization costs, for which the main disease was UC, and outpatient costs including consulting fee, drug cost, examination fee, administrative fee, and related technical fee accounted for the medical cost. Based on the guidelines for UC treatment granted by MHLW, 5-ASA, SASP, corticosteroids, biological products (infliximab, adalimumab), immunosuppressant agents, and devices for cytapheresis were set as target treatments. Biochemical tests, endoscopic examination, ultrasonic inspection, CT, MRI, enema X-ray inspection, etc. were included as target inspections.

RESULTS: The analyzed population was 2,566 (Male 62.2%), and the mean age was 42.8 years. The annual medical cost per patient was $1,457 (1 US$ = 110 yen) (Male: $1,431, Female: $1,501). The annual medical cost of UC treatment in Japan was estimated to be approximately $249 million.

CONCLUSIONS: In this study, the direct medical cost of UC treatment in Japan was estimated. As the UC is a lifelong disease that appears mainly in young adults, the economic impact including productivity loss is expected to be even greater.